Combined high-pressure pneumatic seal

Abstract

The invention belongs to the technical field of sealing, and particularly relates to a combined high-pressure pneumatic seal, which is particularly important to design a pneumatic seal structure because the difficulty of sealing high-pressure gas is far greater than that of liquid. According to the combined pneumatic sealing structure of the sawtooth-shaped structure, the surface part, making contact with the cylinder barrel, of the pneumatic base body is designed to be of the sawtooth-shaped structure, a traditional smooth plane is replaced, and the groove is machined in the middle and used for installing the X-shaped ring; the sawtooth-shaped structure mainly reduces the pressure intensity of fluid in the seal through the echelon property of a plurality of sealing cutting edges, two symmetrical lateral open type grooves are designed in the lower end of the pneumatic base body and used for installing large O rings respectively, and meanwhile a sealing groove is machined in the middle of the bottom end of the pneumatic base body and used for installing small O rings. And the purpose of remarkably improving the backpressure pre-tightening force and the sealing effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sealing, and in particular relates to a combined high-pressure pneumatic seal suitable for a high-pressure working environment. Background Art

[0002] The sealing structure is an important structure to ensure the normal operation of mechanical equipment. It is mainly used to control the leakage behavior of the mechanical structure to save materials, save energy and reduce costs. High-pressure pneumatic seals are much more difficult than hydraulic seals because they need to effectively isolate high-pressure gases. It is particularly necessary to improve the sealing anti-microleakage performance and effectively improve reliability through structural improvement design. At present, it is necessary to propose a new type of high-pressure pneumatic seal to address the performance and reliability risks and deficiencies of existing pneumatic seals. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The technical problem to be solved by the present invention is: how to provide a combined high-pressure pneumatic seal that can significantly improve the sealing effect of high-pressure fluid media.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a combined high-pressure pneumatic seal, which comprises: a pneumatic base (6), an X-shaped ring (8), a large O-ring (9), and a small O-ring (10); the surface portion of the pneumatic base (6) in contact with the cylinder is provided with a sawtooth structure (7), and a groove is processed in the middle of the peak of the pneumatic base (6) for installing the X-shaped ring (8);

[0007] Two symmetrical sideways open grooves are arranged at the lower end of the pneumatic base (6) for installing large O-rings (9) respectively. Meanwhile, a sealing groove is processed at the middle part of the bottom end of the pneumatic base (6) for installing a small O-ring (10).

[0008] Wherein, with the X-shaped ring (8) as the central dividing point, the number of serrations of the serrated structure (7) on the surface of both sides of the pneumatic base (6) is set to 2-3.

[0009] Wherein, the pneumatic base (6) is made of polytetrafluoroethylene material.

[0010] Wherein, the X-shaped ring (8), the large O-ring (9) and the small O-ring (10) are made of rubber material.

[0011] Wherein, the pre-compression rate of the large O-ring (9) is set to be greater than that of the small O-ring (10).

[0012] The pre-compression rate of the large O-ring (9) is set at 18%-22%, and the compression rate of the small O-ring (10) is set at 16%-18%.

[0013] When the combined high-pressure pneumatic seal is installed in a closed pneumatic seal groove (11), the pneumatic base (6) is first heated, and then the combined high-pressure pneumatic seal is installed in the pneumatic seal groove (11) by means of a tool.

[0014] Wherein, the heating temperature is controlled at 80°C-100°C.

[0015] The large O-ring (9) is used to provide sufficient pre-tightening force for the surface of the sawtooth structure (7), and the small O-ring (10) is used to provide sufficient pre-tightening force for the X-shaped ring (8). Through comparative tests, the pre-compression rate of the large O-ring (9) should be greater than that of the small O-ring (10), thereby providing the sawtooth structure (7) with sufficient pre-tightening force to fit the surface.

[0016] The pre-compression rate of the large O-ring (9) is set at 18%-22%, and the compression rate of the small O-ring (10) is set at 16%-18%, forming a series pre-compression structure with the X-ring (8), which can further improve the sealing effect of the X-ring (8).

[0017] (III) Beneficial effects

[0018] In view of the performance and reliability risks and deficiencies of existing pneumatic seals, the present invention proposes a new serrated structure, and at the same time adds an O-ring back pressure energy storage measure at the bottom end of the pneumatic base. Through experimental verification, the leakage resistance of the whole seal under strong impact conditions is significantly improved, and the phenomenon of seal damage is effectively avoided by means of step-by-step decompression. It has been applied in key projects.

[0019] The beneficial effect of the present invention is that, compared with the existing AQ pneumatic sealing technology, the present invention has proposed a combined pneumatic sealing structure with a serrated structure after repeated tests, and the surface portion of the pneumatic base 6 in contact with the cylinder is designed to be a serrated structure 7, which replaces the traditional smooth plane, and reduces the fluid pressure inside the seal in a step-by-step manner through multiple sealing edges, reduces the impact pressure on the X-ring 8, and effectively reduces the initial contact area and friction between the combined seal and the inner wall of the cylinder. Through experimental tests, it is stipulated that the number of serrations on the surface of each side of the pneumatic base 6 should be designed to be 2-3 with the X-ring 8 as the dividing point to achieve a more ideal state. In addition, compared with the prior art, a sealing groove is processed in the middle part of the bottom end of the pneumatic base 6 for installing a small O-ring 10, mainly to provide sufficient pre-tightening force for the X-ring 8. At the same time, it is stipulated that the pre-compression rate of the large O-ring 9 should be set at 18%-22%, and the compression rate of the small O-ring 10 should be set at 16%-18%, forming a series pre-compression structure with the X-ring 8, which can further improve the sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a self-pressurizing energy storage seal;

[0021] Figure 2 It is a traditional energy storage sealing structure;

[0022] Figure 3 It is a self-pressurizing energy storage seal pressurization bonding diagram;

[0023] Figure 4 This is the pressurized deformation diagram of the self-pressurizing accumulator;

[0024] Figure 5 This is a structural diagram of a combined pneumatic seal.

[0025] In the figure, 1-sealed shaft; 2-dovetail jacket; 3-V-shaped spring; 4-triangular block; 5-sealing cavity; 6-pneumatic base; 7-serrated structure; 8-X-shaped ring; 9-large O-ring; 10-small O-ring; 11-pneumatic sealing groove. DETAILED DESCRIPTION

[0026] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0027] In order to solve the above technical problems, the present invention provides a combined high-pressure pneumatic seal, which comprises: a pneumatic base (6), an X-shaped ring (8), a large O-ring (9), and a small O-ring (10); the surface portion of the pneumatic base (6) in contact with the cylinder is provided with a sawtooth structure (7), and a groove is processed in the middle of the peak of the pneumatic base (6) for installing the X-shaped ring (8);

[0028] Two symmetrical sideways open grooves are arranged at the lower end of the pneumatic base (6) for installing large O-rings (9) respectively. Meanwhile, a sealing groove is processed at the middle part of the bottom end of the pneumatic base (6) for installing a small O-ring (10).

[0029] Wherein, with the X-shaped ring (8) as the central dividing point, the number of serrations of the serrated structure (7) on the surface of both sides of the pneumatic base (6) is set to 2-3.

[0030] Wherein, the pneumatic base (6) is made of polytetrafluoroethylene material.

[0031] Wherein, the X-shaped ring (8), the large O-ring (9) and the small O-ring (10) are made of rubber material.

[0032] Wherein, the pre-compression rate of the large O-ring (9) is set to be greater than that of the small O-ring (10).

[0033] The pre-compression rate of the large O-ring (9) is set at 18%-22%, and the compression rate of the small O-ring (10) is set at 16%-18%.

[0034] When the combined high-pressure pneumatic seal is installed in a closed pneumatic seal groove (11), the pneumatic base (6) is first heated, and then the combined high-pressure pneumatic seal is installed in the pneumatic seal groove (11) by means of a tool.

[0035] Wherein, the heating temperature is controlled at 80°C-100°C.

[0036] The large O-ring (9) is used to provide sufficient pre-tightening force for the surface of the sawtooth structure (7), and the small O-ring (10) is used to provide sufficient pre-tightening force for the X-shaped ring (8). Through comparative tests, the pre-compression rate of the large O-ring (9) should be greater than that of the small O-ring (10), thereby providing the sawtooth structure (7) with sufficient pre-tightening force to fit the surface.

[0037] The pre-compression rate of the large O-ring (9) is set at 18%-22%, and the compression rate of the small O-ring (10) is set at 16%-18%, forming a series pre-compression structure with the X-ring (8), which can further improve the sealing effect of the X-ring (8).

[0038] Example 1

[0039] This embodiment provides a combined high-pressure pneumatic seal. The main function of the pneumatic seal is to seal high-pressure gas, especially in oil and gas suspension actuators. Since it is much more difficult to seal high-pressure gas than liquid, how to design the pneumatic seal structure is particularly important. The traditional combined pneumatic seal is mainly composed of a pneumatic base 6, an X-shaped ring 8 and two large O-rings 9. After repeated tests, the present invention proposes a combined pneumatic seal structure with a serrated structure, which is improved. Figure 5 In the novel pneumatic sealing structure shown, the entire pneumatic seal is installed in the pneumatic sealing groove 11, and the surface portion of the pneumatic base 6 in contact with the cylinder is designed to be a serrated structure 7, replacing the traditional smooth plane, and a groove is processed in the middle portion for installing the X-ring 8. The serrated structure 7 mainly reduces the fluid pressure inside the seal in a step-by-step manner through multiple sealing edges, reduces the impact pressure on the X-ring 8, and effectively reduces the initial contact area and friction between the combined seal and the inner wall of the cylinder. Through experimental tests, with the X-ring 8 as the dividing point, the number of serrations on each side surface of the pneumatic base 6 should be designed to be 2-3 to achieve a more ideal state.

[0040] Two symmetrical laterally open grooves are designed at the lower end of the pneumatic base 6 for installing large O-rings 9 respectively. At the same time, a sealing groove is processed in the middle part of the bottom end of the pneumatic base 6 for installing a small O-ring 10. The large O-ring 9 mainly provides sufficient pre-tightening force for the surface of the serrated structure 7, while the small O-ring 10 mainly provides sufficient pre-tightening force for the X-ring 8. Through comparative tests, the pre-compression rate of the large O-ring 9 should be greater than that of the small O-ring 10, mainly to provide the serrated structure 7 with sufficient pre-tightening force to fit the surface. The pneumatic base 6 is made of polytetrafluoroethylene material, and the X-ring 8, the large O-ring 9 and the small O-ring 10 are made of rubber material. Due to the high hardness of polytetrafluoroethylene, through comparative tests, the pre-compression rate of the large O-ring 9 should be set at 18%-22%, and the compression rate of the small O-ring 10 should be set at 16%-18%, forming a series pre-compression structure with the X-ring 8, which can further improve the sealing effect of the X-ring 8. Since the pneumatic seal needs to be installed in a closed pneumatic seal groove 11, the pneumatic base 6 needs to be heated and then the seal is installed in the groove through special tooling. The heating temperature needs to be controlled to 80°C-100°C to ensure that the pneumatic base 6 has good ductility and avoid microcrack damage to the seal.

[0041] In addition to the pneumatic sealing environment, the present invention also mentions the consideration of liquid sealing:

[0042] The present invention provides a self-pressurized energy storage seal, including a sealed shaft 1, a dovetail jacket 2, a V-shaped spring 3, a triangular block 4, and a sealing cavity 5; the front end of the dovetail jacket 2 is open, and a V-shaped spring 3 is installed to open the opening and provide pre-tension. A boss is designed at the open end of the dovetail jacket 2 to limit the V-shaped spring 3 and prevent it from falling out during operation. The tail of the dovetail jacket 2 is designed as a dovetail-type scissor-type structure groove, and the triangular block 4 is installed therein. It is in a clearance fit state under no pressure, and the clearance is set to 0.3mm-0.5mm, so as to reserve enough deformation space for the triangular block 4. During assembly, first install the V-shaped spring 3 into the opening of the dovetail jacket 2 and position it, clamp the boss at the open end, and then embed the triangular block 4 into the dovetail groove of the dovetail jacket 2, and then assemble the whole into the opening sealing groove between the sealing shaft 1 and the sealing cavity 5, such as Figure 1 shown.

[0043] In actual use, the opening direction of the dovetail jacket 2 faces the sealed fluid, and there is no pressure on the back. The sealed fluid will push the dovetail jacket 2 to move towards the triangular block 4 until it fits tightly, eliminating the gap between the two. Figure 3 As the pressure of the sealed fluid increases, the whole system begins to deform, the triangular block deforms under pressure, and the cone angle at its front end will open the dovetail jacket 2, so that the dovetail contacts the sealing wall, as shown in the figure. Figure 4 This contact effect occurs only when the pressure reaches a certain level, and the greater the pressure, the stronger the contact force, which improves the sealing ability of the sealing system. Based on the experience in actual use, the contact threshold pressure is designed to 20Mpa, and the specific structural parameter design is completed through finite element analysis.

[0044] Through sufficient test verification, the sealing form formed by the dovetail structure and the triangular structure has achieved the sealing characteristic that the greater the pressure, the better the sealing effect. Specifically, the dovetail jacket 2 presses the triangular block 4 under the action of fluid pressure, and the triangular block 4 is significantly deformed under the influence of the load, which is manifested as the front end cone angle of the triangular block 4 increases, the height decreases, and the width increases, which in turn causes the dovetail part of the dovetail jacket 2 to be stretched open and contact with the sealing wall surface, forming a new channel to prevent fluid leakage, and increasing the sealing ability of the seal; this increase in sealing ability is related to the deformation of the triangular block 4, and then to the pressure of the sealing fluid, that is, the greater the fluid pressure, the stronger the sealing ability of the seal, which is a self-tightening seal.

[0045] In fact, the above-mentioned structural form focuses on the effect of the sealing shape. Further, the sealing size and sealing material can be restricted. Through analysis, the smaller the initial front end cone angle of the triangular block 4 is, the stronger the effect of pressurized energy storage is. However, too small a cone angle is likely to cause damage during the extrusion process. Through finite element analysis and experimental verification, the front end cone angle of the triangular block 4 is finally set to 60°±5°. When the dovetail jacket 2 and the triangular block 4 are completely in contact and pressed, the front end cone angle is set to 120°±5°. At this time, the energy storage state is optimal, and the extrusion damage of the triangular block 4 can be effectively avoided. The dovetail jacket 2 is set to polyurethane material, and the Shore hardness is set between 80-90 degrees, which is relatively hard. At the same time, the material of the triangular block 4 is made of soft materials such as nitrile rubber, and the Shore hardness is set between 60-70 degrees to enhance the pressurized effect. Through experimental verification, this combination of softness and hardness can achieve the best matching degree of sealing performance and reliability.

[0046] Furthermore, the self-pressurizing energy storage seal and the combined pneumatic seal can be combined in series and used in working environments that require isolation of high-pressure liquid and high-pressure gas media to achieve an ideal sealing state, wherein the self-pressurizing energy storage seal is arranged on the liquid side and the combined pneumatic seal is arranged on the gas side.

[0047] It should be noted that those skilled in the art can easily understand that the self-pressurizing energy storage seal involved in the present invention can be applied to different types of suspension actuators, and different forms of changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention as defined by the attached claims.

Claims

1. A combined high-pressure pneumatic seal, characterized in that: It includes: A pneumatic base (6), an X-shaped ring (8), a large O-ring (9), and a small O-ring (10); the surface portion of the pneumatic base (6) in contact with the cylinder is provided with a sawtooth structure (7), and a groove is processed in the middle portion of the peak of the pneumatic base (6) for installing the X-shaped ring (8); Two symmetrical sideways open grooves are arranged at the lower end of the pneumatic base (6) for installing large O-rings (9) respectively. Meanwhile, a sealing groove is processed at the middle part of the bottom end of the pneumatic base (6) for installing a small O-ring (10).

2. The combined high pressure pneumatic seal according to claim 1, characterized in that: With the X-shaped ring (8) as the central dividing point, the number of serrations of the serrated structure (7) on the surfaces of both sides of the pneumatic base (6) is set to 2-3.

3. The combined high pressure pneumatic seal according to claim 1, characterized in that: The pneumatic base (6) is made of polytetrafluoroethylene material.

4. The combined high pressure pneumatic seal according to claim 1, characterized in that: The X-shaped ring (8), the large O-ring (9) and the small O-ring (10) are made of rubber material.

5. The combined high pressure pneumatic seal according to claim 4, characterized in that: The pre-compression rate of the large O-ring (9) is set to be greater than that of the small O-ring (10).

6. The combined high pressure pneumatic seal according to claim 5, characterized in that: The pre-compression rate of the large O-ring (9) is set at 18%-22%, and the compression rate of the small O-ring (10) is set at 16%-18%.

7. The combined high pressure pneumatic seal according to claim 1, characterized in that: When the combined high-pressure pneumatic seal is installed in a closed pneumatic seal groove (11), the pneumatic base (6) is first heated, and then the combined high-pressure pneumatic seal is installed in the pneumatic seal groove (11) by means of a tool.

8. The combined high pressure pneumatic seal according to claim 7, characterized in that: The heating temperature is controlled at 80°C-100°C.

9. The combined high pressure pneumatic seal according to claim 6, characterized in that: The large O-ring (9) is used to provide sufficient pre-tightening force for the surface of the sawtooth structure (7), and the small O-ring (10) is used to provide sufficient pre-tightening force for the X-shaped ring (8). Through comparative tests, the pre-compression rate of the large O-ring (9) should be greater than that of the small O-ring (10), thereby providing the sawtooth structure (7) with sufficient pre-tightening force to fit the surface.

10. The combined high pressure pneumatic seal according to claim 9, characterized in that: The pre-compression rate of the large O-ring (9) is set at 18%-22%, and the compression rate of the small O-ring (10) is set at 16%-18%, forming a series pre-compression structure with the X-ring (8), which can further improve the sealing effect of the X-ring (8).

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